This invention relates to an automotive seat head restraint assembly and in particularly to a locking mechanism for the head restraint assembly that provides detents for various extended positions of the head restraint and a means for preventing inadvertent removal of the head restraint pad from the associated seat.
Motor vehicle manufacturers provide head restrains for occupant seats as a comfort and safety feature. Head restraints provide a surface upon which the seat occupants can rest their heads against and also provide occupant protection by controlling rearward excursion of the occupant's head in rear impact situations.
Head restraints can be categorized as several different general types. The so-called integral head restraint or "high back" seat has a seat back with a vertical extension forming a head restraint. Another type of seat has a separate head restraint pad extending upwardly above the seat back and frequently has a mechanism for allowing the vertical position of the pad to be adjusted and positioned for a particular seat occupant. Vertical adjustment of these types of head restraints is typically accomplished by providing one or more posts extending from the head restraint pad into the seat back, with a mechanism mounted within the seat back for allowing the position of the head restraint pad to be adjusted and set at a desired position. As a means of preventing inadvertent removal of the head restraint from the seat back, which could occur during adjustment, a latch or stop may be provided which limits the upward extend of adjustment of the head restraint pad. Means are further often provided for unlatching the stop to enable the head restraint pad to be removed from the seat back for vehicle repairing, servicing, retrimming, etc.
While numerous designs for head restraint assemblies of the above type are known, manufacturers of motor vehicle components are constantly striving to increase productivity by simplifying seat assembly. One method of locking the head restraint in different vertical positions uses tubular plastic guides having a transverse spring loaded steel plate engaging notches in the post to hold the head restraint in place. This mechanism contains several individual components requiring considerable assembly time.
Another problem with this type of locking mechanism is that the sharp edge of the spring loaded plate scrapes the coating off the head restraint post. The most durable coating found has been chrome. However, chrome is often not acceptable or desired by the vehicle designer. Instead, a phosphate and oil coating is often chosen because, when scratched, it is not as noticeable as with other coatings. However, a phosphate and oil coating has a dull finish and the resultant appearance is also often not desired. Furthermore, because of the oil base in the coating, extra care must be used in order to keep the oil from soiling the seat trim covers. A major disadvantage with a phosphate and oil coating is the varied efforts required to raise and lower the head restraint. This variation in effort is largely due to the inconsistent thickness of the phosphate being applied to the head restraint post. Since the spring loaded locking plate is the primary contributor to the adjustment effort, the amount of coating built up in the notches can greatly vary the effort required to adjust the head restraint. When there is a large amount of phosphate built up in the notches, the plate sticks and more force is required to adjust the head restraint.
Accordingly, it is an object of the present invention to provide a head restraint adjustment mechanism that reduces the number of individual components in the mechanism and the time required to assemble the mechanism.
It is a further objective of the present invention to eliminate scratching of the head restraint post coating to enable a wider range of coatings to be used on the post.
It is yet another objective to provide a head restraint locking mechanism in which the adjustment efforts are repeatable from one mechanism to another and in which the particular coating of the head restraint post has little or no effect on the adjustment effort.
The locking mechanism of the present invention is designed with a generally V-shaped spring clip for engagement in like shaped notches in the head rest post. Instead of a sharp edge, the spring clip has a rounded edge engaging the post to reduce or eliminate scratching of the coating. The spring clip includes a cut out portion that catches a locking notch having a lower square edge to keep the head restraint from being inadvertently pulled out of the seat back.
The spring clip is held within a housing molded in a tubular plastic bushing. The bushing is inserted into a metal sleeve attached to the seatback frame. The head restraint post is inserted into the bushing where the spring clip engages the notches in the head restraint post.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.